general: python3.9 reached EOL, switch min version

also enable 3.13 on CI

my/core/utils/concurrent.py

@@ -1,6 +1,6 @@
 import sys
 from concurrent.futures import Executor, Future
-from typing import TYPE_CHECKING, Any, Callable, Optional, TypeVar
+from typing import Any, Callable, Optional, TypeVar
 
 from ..compat import ParamSpec
 
@@ -19,33 +19,21 @@ class DummyExecutor(Executor):
         self._shutdown = False
         self._max_workers = max_workers
 
-    if TYPE_CHECKING:
-        if sys.version_info[:2] <= (3, 8):
-            # 3.8 doesn't support ParamSpec as Callable arg :(
-            # and any attempt to type results in incompatible supertype.. so whatever
-            def submit(self, fn, *args, **kwargs): ...
+    def submit(self, fn: Callable[_P, _T], /, *args: _P.args, **kwargs: _P.kwargs) -> Future[_T]:
+        if self._shutdown:
+            raise RuntimeError('cannot schedule new futures after shutdown')
 
+        f: Future[Any] = Future()
+        try:
+            result = fn(*args, **kwargs)
+        except KeyboardInterrupt:
+            raise
+        except BaseException as e:
+            f.set_exception(e)
         else:
+            f.set_result(result)
 
-            def submit(self, fn: Callable[_P, _T], /, *args: _P.args, **kwargs: _P.kwargs) -> Future[_T]: ...
-
-    else:
-
-        def submit(self, fn, *args, **kwargs):
-            if self._shutdown:
-                raise RuntimeError('cannot schedule new futures after shutdown')
-
-            f: Future[Any] = Future()
-            try:
-                result = fn(*args, **kwargs)
-            except KeyboardInterrupt:
-                raise
-            except BaseException as e:
-                f.set_exception(e)
-            else:
-                f.set_result(result)
-
-            return f
+        return f
 
     def shutdown(self, wait: bool = True, **kwargs) -> None:  # noqa: FBT001,FBT002,ARG002
         self._shutdown = True